Is it possible to identify a strain by observing the plants flower?
No. The only thing you can really tell is whether it’s a sativa, indica or hybrid.
I can tell which strains are which in my tent during flower, but that’s because I’m familiar with their scent, leaves, and overall appearance.
I’d be hard pressed to differentiate between strains, (even familiar ones) through just pics.
Yup as they flower the smells, growing patterns, etc etc help. Google your strain and look at a couple others